It is known to expand a tubular downhole in a well using a Jack And Pull (JAP) assembly which is cyclically extended and retracted.
There is a need to provide an improved Jack And Pull (JAP) liner expansion tool that enables:                The drill pipe to be cleaned during cementation by a two stage trailing cement plug provided with elastomer scrapers wiping the inner wall of the drill pipe.        The second stage of the plug to be released from the first stage upon seating to close off the bore of the expansion assembly which allows the jack to be operated.        The cement to be flushed from the bore of the expansion tool string below the jack through the use of an annular non-return valve and a non-return valve in the bore of the expansion tool string.        The area below the cone to be filled with mud while stroking the jack.        
It is an object of the present invention to provide an improved method and system that meet these objectives and overcome drawbacks of the known JAP assembly.